Large amounts of content are delivered regularly over the Internet. The content serves a wide variety of purposes, such as one-time display (e.g., streaming audio and video for entertainment and news purposes), commerce (e.g., text, video and graphics for advertising and sales purposes), downloadable media such as books and documents, and many others. Content Delivery Networks (CDNs) are often seen as providing “capacity of last resort” for companies that provide content, or services that involve content, over the Internet.